Lead compound and method of making same.



ilrntnn Stars MINNIE M. DUBIN, OF PHILADELPHIA, PENNSYLVANIA.

LEAD COMPQUND AND METHOD OF MAKING SAME.

SPECIFICATION forming part of Letters Patent N 0. 670,198, dated March19, 1901 Application filed June 23, 1900. serial No. 21,283. (Nospecimens.)

To (0Z8 whom it may concern:

Be it known that I, MINNIE M. DUBIN, a subject of the Emperor of Russia,residing at Philadelphia, county of Philadelphia, and State ofPennsylvania, have invented a new and useful Improvement in Methods ofBendering Lead in Sodium Plumbate Insoluble, of which the following is afull, clear, and eX- act description.

My invention relates to a novel process of acting upon sodium plumbate,a comparatively rare compound which is incidentally produced in themanufacture of certain other productsas, for example, in the manufactureof nitrite of soda-so as to form an insoluble lead compound.

My invention consists, broadly, in acting upon a solution of sodiumplumbate with a sulfid or hydro-sulfid of a metal of the alkalineearthgroup, as barium or calcium, the reaction resulting in precipitating thelead as an insoluble double salt of sulfid of lead and oXid of thealkaline-earth metal used.

My invention further consists in the novel j product thus obtained.

My invention further consists in the reaction above described whenmanufacturing nitrite of soda, whereby the disadvantages of using nitricacid (now used to remove the sodium plumbate from solution) are avoidedand whereby the by-product formed is an insoluble double salt, readilyremovable from the solution of nitrite of soda.

In the manufacture of nitrite of soda as now ordinarily carried on thissalt is obtained by the fusion of lead and nitrate of soda, the leadreducing the nitrate to nitrite, and the oxid of lead thus formed beingof course insoluble, and therefore readily removable from thenitrite-of-soda solution. There is, however, a small amount of causticsoda produced in the reaction, which reacting with the lead oXidproduces a sodium plumbate. This is soluble and must be removed from thenitrite of soda.

By my method I am enabled to carry on the manufacture of nitrite of sodaat a much less cost, only a small amount of the sulfid being required,and with the production of the insoluble double salt of lead and thealkaline-earth metal, which is readily removable from the solution. Iadd to the solution of nitrite of soda and plumbate of soda a sulfid orhydro-sulfid of an alkaline earth and obtain the following reaction withthe sodium plumbate, supposing barium sulfid to be the specific sulfidchosen:

the insoluble by-product being the barium oXy-lead sulfid. Of course Imay also use a hydro-sulfid, the reaction being the same in principle,thus- Again, I may, if I prefer, use any other metal of thealkaline-earth group, if desired, and the reaction will be the same.

In view of What I have herein set forth it is obvious that I do notdesire to limit myself to the exact reactions, the formulae of Which Ihave given. Further, where in the appended claims I refer to a sulfid ofbarium or, more broadly, to a sulfid of a metal of the alkaline-earthgroup I intend that a hydro-sulfid shall be a full equivalent thereof.Moreover, I do not desire to limit myself in all cases to theapplication of my broad invention to the manufacture of nitrite of soda,as my invention may be used with any solution containing plumbate ofsoda.

Having now fully described my invention, what I claim, and desire toprotect by Letters Patent, is

1. The process herein set forth of acting upon solutions containingsodium plumbate which consists in combining therewith, sulfid of a metalof the alkaline-earth group.

2. The novel metallic compound herein described being a double sulfid oflead and oXid of a metal of the alkaline-earth group.

3. In the manufacture of nitrite of soda the process herein described ofdecomposing the sodium plumbate formed from the nitrite of soda,consisting in treating the solution with sulfid of a metal of thealkaline-earth group.

In testimony of which invention 1 have hereunto set my hand, atPhiladelphia, Pennsylvania, on this 22d day of June, 1900.

MINNIE M. DUBIN.

Witnesses:

MINNIE F. ELLIS, J. M. SHINDLER, J r.

